US 9,000,752 B2 · Multi-conductor cable current and voltage sensors

Abstract

A detachable current sensor provides an isolated and convenient device to measure current passing through a cable such as an AC power cable or non-metallic (NM) sheathed cable. Information about the magnitude and or phases of the currents passing through and/or voltages on the conductors is obtained by measuring the magnetic field at multiple circumferential positions around the cable using multiple semiconductor magnetic field sensors. A processing subsystem coupled to the multiple semiconductor magnetic field sensors determines information about the currents flowing in the conductors of the cable, including the current magnitude(s), and/or the phases and number of phases present in the cable, which can form part of a power measurement system that is used for energy monitoring, and/or for control purposes.

Claims19

Dependent claims

A sensor for sensing properties of currents passing through conductors in a multi-conductor cable, the sensor comprising:

a housing for detachably coupling the sensor to the cable, wherein the housing defines an opening for receiving the cable when the sensor is coupled to the cable;
a plurality of semiconductor magnetic field sensors integrated in the housing and disposed circumferentially around the opening, whereby at least some of the semiconductor magnetic field sensors are located at differing distances from the conductors when the sensor is coupled to the cable, wherein the plurality of semiconductor magnetic field sensors provide corresponding outputs indicative of the properties of the currents that differ due to the differing distances;
and
a plurality of ferrite bodies corresponding to the semiconductor magnetic field sensors and disposed between the corresponding semiconductor magnetic field sensors and the opening.

1 more element

A method for sensing properties of currents passing through conductors in a multi-conductor cable, the method comprising:

detachably coupling a housing of a current sensor around the cable;
measuring a magnetic field property at multiple circumferential positions around a cable in a plane substantially perpendicular to the direction of current flow in the cable using multiple semiconductor magnetic field sensors disposed at the multiple circumferential positions around the cable;
concentrating a magnetic field generated by the currents at the multiple circumferential positions by providing a plurality of ferrite bodies corresponding to the semiconductor magnetic field sensors and disposed between the semiconductor magnetic field sensors and the cable;
and
determining properties of currents flowing in the conductors of the cable from results of the measuring.

2 more elements

Dependencies are inferred from the claim text.

Multi-conductor cable current and voltage sensors

Life of this patent

Multi-conductor cable current and voltage sensors

Life of this patent

Abstract

Claims19